C.R.S. § 42-7-418

(1) A person may give proof of financial responsibility by delivering to the director money in an amount or securities approved by said director and of a market value in a total amount as would be required for coverage in a motor vehicle liability policy furnished by the person giving such proof under this article. Such securities shall be of a type which may legally be purchased by savings banks or for trust funds. (2) All money or securities so deposited shall be subject to execution to satisfy any judgment mentioned in this article but shall not otherwise be subject to attachment or execution.